The present invention relates to a system for diagnosing the operation or servicing of air conditioner systems, such as automobile air conditioner systems, for use alone or in conjunction with an automatic air conditioner charging station for charging refrigerant and oil into air conditioner systems.
There have been provided disclosures of a number of systems for diagnosing the operation or servicing of such air conditioners. Motl U.S. Pat. No. 3,686,954 provides a system for testing or diagnosing an air conditioner using solenoid valves actuated by manually operated switchers; the temperatures and pressures of the system are measured and readouts are provided by gauges.
Suzuki et al. U.S. Pat. No. 4,663,940 disclose a self-diagnostic apparatus for an automobile air conditioner which utilizes a microprocessor, input signals to which include sensing the position of dampers in air flow ducts. Also, of general interest are Hara U.S. Pat. No. 4,488,409 and Iida U.S. Pat. No. 4,688,389.
A number of apparatus have also been provided for automatically charging such air conditioners. Among those are Proctor et al. U.S. Pat. No. 4,513,578 and Proctor U.S. Pat. No. 4,624,112. The former patent discloses an air conditioner charging station having a weighing scale on which are mounted reservoirs for oil and refrigerant, and an electronic sequencing unit, or microprocessor, which senses the weight loss of the reservoirs as first oil is charged into the air conditioner and then refrigerant is charged into the air conditioner, the amount of each which is charged into the air conditioner being determined by an operator entering into the computer the required amounts of oil and refrigerant for a particular air conditioner. Proctor U.S. Pat. No. 4,624,112 discloses a system of that general type, in which there is provided a conduit connecting the high and low pressure side conduits, called a cross-over conduit, and having a solenoid operated valve in it, together with a solenoid operated dump valve for dumping refrigerant and oil.
Sparano U.S. Pat. No. 3,232,070 conducts withdrawn refrigerant through a compressor and condenser, and then to a drier strainer, from which it is placed into a storage tank.
Taylor U.S. Pat. No. 3,699,781 provides a refrigerant recovery system in which the refrigerant gas is cooled in order to remove liquid by causing condensation in a coil, prior to introduction of the refrigerant into a drier.
Koser U.S. Pat. No. 4,285,206 discloses a system which is capable of simultaneously connecting a refrigerant recovery and purificatio apparatus to the air conditioner systems of two vehicles and includes a reclaim refrigerant tank mounted on a scale, and a tank for new refrigerant, one air conditioner system being recharged with reconditioned refrigerant while the other air conditioner system is having the refrigerant therein withdrawn for reclaiming.
Lower et al. U.S. Pat. No. 4,364,236 and Lower et al. U.S. Pat. No. 4,441,330 provide a system in which refrigerant is withdrawn from an air conditioner and passes through a particulate filter, an evaporator, an oil separator, a compressor, a condenser, and to a reservoir, and thence to a purifier, purified refrigerant from the reservoir being charged into an air conditioner being serviced; a microprocessor is used to effect the sequencing of the operations.
Goddard U.S. Pat. No. 4,476,688 discloses a refrigerant recovery and purification system in which refrigerant is withdrawn from an air conditioner and passed through an oil separator and a filter-drier by a compressor and into a receiving tank for the reclaimed refrigerant. The refrigerant is delivered from the reclaim tank, for charging into the air conditioner. A purge valve and a high pressure switch for a condenser are provided to bleed off air when air pressure in the condenser-evaporator becomes excessive. Such excess pressure causes the compressor to be shut down.
Margulefsky et al. U.S. Pat. No. 4,480,446 provides a system for rehabilitating refrigerant including a filtering tank with a disc-shaped filter.
Taylor U.S. Pat. No. 4,646,527 provides a refrigerant recovery and purification system which includes a compressor and an oil separator, and accumulators having heat exchange coils in them, the recovered refrigerant being placed in a storage tank; in this system, distillation is utilized to separater oil and other impurities from the refrigerant.
Cain U.S. Pat. No. 4,261,178 and Cain U.S. Pat. No. 4,363,222 disclose a refrigerant recovery system in which refrigerant is withdrawn and directed to a cylinder on a scale; there is also disclosed a separate system in which a pump produces a vacuum in a tank, which is then connected with an air conditioner in order to remove part of the refrigerant from it.
Staggs et al. U.S. Pat. No. 4,539,817 provides a refrigerant recovery apparatus which includes a compressor and filters, and a storage tank.
Saunders U.S. Pat. No. 4,106,306 provides a charging apparatus for charging a refrigeration system of the type having a capillary tube, and discloses an electrical circuit for controlling the charging, which circuit receives data relating to indoor and outdoor temperature, to suction line temperature and to suction line pressure.